The number of cases reported in the first half of 2010 (from January to June) was 7,480. The graph below (Figure 1) shows the trend in the semiannually (i.e., six months') figures for the cases reported to IPA.

As shown in Figure 1, the number of cases had been on the decrease until the first half of 2010, when the figure increased from the second half of 2009.

Figure 1: Trend in the Number of Cases Reported to IPA

As with the virus report count, the virus detection count has been decreasing for this one-year period. The reason should be the decrease in the detection count of W32/Netsky, for which the largest number of reports have been submitted to IPA.

Meanwhile, detection count for W32/Mumu increased from January to March 2010, while that for W32/Waledac increased in January 2010. These viruses have a feature to spread infection thought an email attachment and are suspected to have been distributed in large quantity at that time

Apart from W32/Netsky or other viruses that are still prevalent, new type or subspaces of a virus might emerge and be distributed in large quantity. So we need to be careful about handling email attachments.

Figure 2: Trend in the Virus Detection Count

Looking at the trend in virus report count, we can see that as in the past, there have been a number of reports concerning W32/Netsky. From January to March 2010, reports concerning W32/Autorun, which spreads infection through USB memory, were on the rise. You should be aware of the possibility of a virus being contained in USB memory.

To prevent damages caused by these viruses, be sure to apply security patches, use antivirus software, and handle email attachments with care as well as to implement security countermeasures for USB memory on a daily basis.

Figure 3: Trend in the Number of Cases Reported, Classified by Computer Virus

IT Security Center, Information-technology Promotion Agency, Japan (IPA/ISEC)
Hanamura/Kagaya/Ooura
Tel:+81-3-5978-7527
Fax:+81-3-5978-7518
E-mail: